Fair Value Measurements (Narrative) (Details)	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Maximum [Member]	Mar. 31, 2013 Maximum [Member]	Mar. 31, 2014 Minimum [Member]	Mar. 31, 2013 Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Prepayment Rate	1.00%	1.00%
Annual prepayments maturity	100.00%	100.00%
Additional basis points	1.50%	1.50%
Collateral discount			30.00%	30.00%	20.00%	20.00%